I think most of that savings is from the new clothes washer.
But of course we also just do everything we can in general to save water.
I made an idiot's guide to saving water in the shower a while ago:
I would love to have a greywater system, but there no easy way to seperate out some of the drain pipes from the others.
Also, I have an extremely high water table in my area, so I can't just run water into the ground and expect it to soak up.
I have thought about the concept of doing some greywater re-use inside my house. One concept I had was to recapture shower water to flush the toilet with.
In our country, we basically flush toilets with clean drinking water. Sure seems like a huge waste. If the slightly used shower water could be stored in a small tank, and then THAT gets pumped into the toilet every time it's flushed, that's twice the use out of the same water.
Here's an example of sink water that goes straight into reuse in the toilet:
Sinkpositive: Save Water, Wash Your Hands : TreeHugger
And here's a commercially available sink-to-toilet setup.
How the AQUS Works - WaterSaver Technologies
I would like to do something similar to that, only with the shower, as it would provide a LOT more water, and the additional equipment could be in my crawlspace (think VERY short concrete floor and wall basement) instead of taking up space under the sink.
I did see a fantastic greywater system at a "model home" of the future. However, it was also fantastically expensive, and overkill. It went so far as to have ultraviolet disinfecting lights as part of it. I'm just trying to flush a toilet and save some water, not drink out of it!